FileInfo fi = new FileInfo(sFilePath);
            if (fi.Exists)
            {
                System.Net.Mail.Attachment myAttachment = new System.Net.Mail.Attachment(sFilePath, System.Net.Mime.MediaTypeNames.Application.Octet);
                System.Net.Mime.ContentDisposition disposition = myAttachment.ContentDisposition;
                disposition.CreationDate = System.IO.File.GetCreationTime(sFilePath);
                disposition.ModificationDate = System.IO.File.GetLastWriteTime(sFilePath);
                disposition.ReadDate = System.IO.File.GetLastAccessTime(sFilePath);
                myMail.Attachments.Add(myAttachment);

            }
全部代码我看不懂  你帮我讲一下  有什么作用是最重要的